Magnetic force on moving charges, and how motors work
Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.
A motor coil has 100 turns, and each side has 0.05 m in a 0.1 T field. It carries 0.8 A. What force acts on one side, Bo?
A motor coil has 25 turns, and each side has 0.03 m in a 0.4 T field. It carries 1.2 A. What force acts on one side, Esme?
A proton moves straight across a magnetic field. What does the field do to its path, Jun?
- Leaves it unchanged
- Bends it into a curve
- Speeds it up in a straight line
A proton sits still in a magnetic field. What magnetic force acts on it, Kira?
- None
- A force toward north
- A force toward south
A magnetic force keeps bending a moving electron's path. What happens to its speed, Luz?
- It keeps falling
- It keeps rising
- It stays the same
Milo says a wire lying along magnetic field lines feels the biggest force. Agree or disagree?
- Agree: along the field is strongest
- Agree: the field pushes it along
- Disagree: it feels none
Noah says a current running along a field still gets pushed sideways. Agree or disagree?
- Agree: fields push along their lines
- Agree: any current in a field is pushed
- Disagree: it must cross the field
A loudspeaker has a coil attached to a cone, sitting in a magnet's field. What moves the cone, Ren?
- Air pressure from the room
- Changing current in the coil
- Heat from the magnet
What part of an electric fan makes the blades turn, Tala?
- A light bulb
- A motor
- A battery alone
A toy car's motor is wired to its battery the other way round. What happens, Zee?
- It drives the other way
- It drives faster
- It stops and won't start again